At midnight on New Year's Eve, a vast number of government documents that are secret now will be secret no more. The automatic declassification, which applies to all material that is at least 25 years old unless agencies have sought exemptions for it, will include hundreds of millions of pages from the FBI, the CIA and the National Security Agency.

Historians, who will be digesting these documents for decades, can look forward to millions more every year from now on. They can thank not only President Bill Clinton, who signed the 1995 executive order establishing the declassification policy, but also President George W. Bush, who followed through on it.

Despite its willingness to reveal the secrets of a quarter century ago, the Bush administration -- like the Clinton administration, but with measurably more enthusiasm -- continues to abuse the classification system. It bends the law to hide material it has no legitimate reason to hide, as illustrated by its recent squabble with the American Civil Liberties Union over a document so boring it's hard to see what the fuss was about.

This "Information Paper," dated Dec. 20, 2005, addresses "the permissibility of photographing enemy prisoners of war (EPWs) and detainees in the Iraqi Theater of Operations." It's a little more than three pages long yet highly repetitive.

The take-home message: Journalists may photograph prisoners as long as the individuals are not identifiable and are not pictured "in any manner that might be interpreted as holding them up to public curiosity," in violation of the Geneva Conventions. Soldiers may photograph prisoners only when their official duties require it.

The juiciest part of the document is an admonition that recalls the notorious Abu Ghraib photos: "Detainees will not be photographed, humiliated or placed in positions with sexual overtones." Since the Abu Ghraib pictures came to light in April 2004, people might wonder, as the ACLU puts it, "whether the guidelines were in place prior to the Abu Ghraib scandal and, if not, why it took more than a year after the scandal to issue a policy."

Or they might not. In any case, there is nothing remotely threatening to national security about this summary of military regulations. Yet it was labeled "SECRET" at the top and bottom of every page, and after someone e-mailed it to the ACLU in October, the Justice Department obtained a grand jury subpoena demanding "any and all copies" of it.

The subpoena's breadth indicated that its aim was not to investigate a possible crime (in this case, violation of the Espionage Act) but to prevent the dissemination of classified material. This appears to be an unprecedented use of a grand jury subpoena, which is supposed to be used to obtain information, not suppress it.

The ACLU filed a motion to quash the subpoena, arguing that the government was abusing the grand jury process to achieve what amounted to a prior restraint on speech, aimed at stopping the ACLU from publicizing the document's contents. At a Dec. 11 hearing, U.S. District Judge Jed Rakoff seemed inclined to agree.

"There seems to be a huge difference between investigating a wrongful leak of a classified document and demanding all copies of it," Rakoff noted. "I wonder what the authority is for using a grand jury subpoena for that purpose." He also alluded to the 1971 "Pentagon Papers" case, in which the U.S. Supreme Court said the government may not prevent publication of classified material unless it would cause "direct, immediate, and irreparable damage to our Nation or its people."

One week after that hearing, the Justice Department, suddenly realizing "the grand jury can obtain the evidence necessary to its investigation from other sources," dropped its subpoena. The document, deemed "secret" just a year ago based on criteria that are hard to fathom, was declassified on Dec. 15 for reasons equally mysterious. This is the sort of thing that gives secrets a bad name.